bitdump
Tekko32 F3 4in1 (version B) Desync Bidirectional Dshot
Hi,
I have an issue with these ESC, when i am at low rpm and give full throttle the quad stop and drop it's falling out of the sky like it shuts off.
https://youtu.be/s030Vkzg6Bg
To Reproduce
Turn ON RPM filter (bidirectional Dshot) Whit no RPM filter is ok
Setup / Versions
- Holybro F7 HDV and Tekko32 F3 4in1 B;
- DJI Vista
- Motors 2306 1750kV
issue with betaflight 4.1 et 4.2 BLheli 32.7
There have been reports of some units of the Tekko32 F3 4in1 B ESC that resets when running 6S. You should contact your vendor about this.
@sskaug The Betaflight team is receiving lots of reports of bidirectional DSHOT telemetry errors when running DSHOT600 on these and other F3-based ESCs. The errors increase with RPM. Problem seems to be reduced when running DSHOT300.
Additionally there are many reports of intermittent protocol detection problems with the ESCs failing to initialize, or the initialization is delayed and out-of-sync between the motors. Seems to be related to F3-based ESCs (not one particular model/brand). Problem only seems to be related to inverted DSHOT detection.
Taken across all the reports it seems to be some generalized problem with inverted DSHOT handling on the F3-based ESCs. Disabling bidirectional DSHOT and using the normal non-inverted DSHOT seems to resolve the problems.
@etracer65 Thanks for the input. We will try to understand what is is going on here.
This is probably related:
https://github.com/betaflight/betaflight/issues/9886#issuecomment-655085419
The ESC is sending telemetry responses too soon before the FC has had a chance to transition the GPIO pin to INPUT mode.
I have the exact same issue. On hard punchouts one or more motors (usually both front motors) would appear to desync and the quad would fall out of the sky. However, if I rearmed the quad after the crash only some of the motors would start spinning the others would remain still. Power cycling the quad would get all 4 motors spinning again until the next 'desync' event. In my experience a motor desync has never caused the ESC to refuse to spin the motor until being power cycled so this may be something new.
I found that behaviour significantly improved with timing set to auto, PWM to 48kHz (lowest possible for this ESC) and demag to high. I am using BF 4.2.0 with bidir DSHOT enabled.
I am happy to help test fixes for this issue.
@etracer65 There appears to be an issue with the FC not sending any DSHOT commands at all. See @jhartley 's comments here https://github.com/betaflight/betaflight/issues/9886#issuecomment-657829904
Issue still persists with 32.71 beta firmware for Tekko32 F3 4in1 B. It appears to be an issue with 96kHz PWM. No deathroll on 48kHz PWM frequency.
Potentially related is a loss of authority at zero throttle (lots of wobbles and bobbles) also seen at 96kHz PWM and not at 48kHz PWM.
@MimNanopirate I'm finding that I don't have a problem if I set the PWM to 48kHz. I hope this helps you too as we're running the same stack. No need to disable bidirectional dshot. You might also benefit from this test code: https://github.com/bitdump/BLHeli/tree/master/BLHeli_32%20ARM/Bidir%20Dshot%20F3%20testcode
I have the exact same issue @ChrisRosser describes with the same ESC. This behaviour of some motors not spinning at all after a rearm but fine after reboot is not something I've ever encountered or heard of before. Motor timing doesn't seem to affect it (Tried auto and 23, eventually happened on both) but 96khz definitely brings up this amongst other problems. On 96khz this is almost guaranteed to happen on the first punchout if not before, but aside from this the quad just flies terrible, lots of oscillations and loss of authority, even the motors make a strange noise.
I have contacted Holybro and received no reply. I find it very suspicious that this ESC has been pulled out of the market and a new version has been introduced with only one difference:
The PCB design uses a design in which the drive circuit and the control circuit are separated. This design broadens the overcurrent capability of the drive circuit, and at the same time reduces the electrical interference to the control circuit.
In my view, electrical interference doesn't manifest itself as a loss of performance but rather as a catastrophic failure like we're seeing. If Holybro is aware that the product had electrical interference problems they should recall it.
Had a few more flights. I noticed the issue is much more likely to occur when the battery is full. Trying to do a "punch to the moon" with a fully charged 6S is a reliable way to reproduce. Once the battery is down to 80% or lower it takes a lot of tries to bring out the issue. Can provide blackbox logs if it helps.
@bluehallu Thanks for reporting that you are having the issue too. I happen to have a just received a new tekko32 with separated control. I'll build it into a quad in the next fortnight and we can see if it does the same thing! I haven't had any issues on 48kHz PWM. Do you have any issues on 48kHz? It might be that 96KHz PWM on BLHELI_32 is still quite new and it needs to mature a little before its suitable for daily driving.
Do you have a problem if you disable bidirectional DShot? I haven't tried this myself but people have suggested it.
Yeah, as I said above I get problems even at 48khz. Holybro finally agreed to replace both ESCs (I hope with the new version) so I was quite happy to just be careful in the meantime but I just came back from the field and it was... bad. The ESC set itself in flames mid flight charring everything around it and puffing my battery... My advice to anyone with this ESC is to never run on it 6S or get it replaced.
@bluehallu Whoa! That escalated quickly! Sorry to hear that buddy. Were you running the 1000uF cap?
So, as I had two of these ESCs (I built two identical quads), I'm on holiday and while I wait for HolyBro to send me the new ones I thought I'd keep trying things with the other one so I spent the whole day at the field today. I tried demag on high, turning off bidirectional Dshot, dshot 300, and even swapped wires on reversed motors so that no motor had to be reversed in blheli.
None of this helped and it would still occasionally fall off the sky with the usual "motor doesn't turn back on until power cycle". When in this state and before power cycling, rebooting the FC doesn't help, trying to spin the motors from motor tab doesn't do anything and indeed Blheli32 app doesn't even detect the ESCs. I also noticed that sometimes more than one ESC would get in this state, and the ESCs this happened on seemed totally random. I saw it happen at least once in all 4.
Now the best part is that in the end after a full deflection yaw it fell from the sky again but this time it never recovered. I found it in the grass making a strange noise (video https://youtu.be/JRJi9tedTV4), and now after powering it either makes that noise after the initial startup tones or only some motors spin and others either don't move or the propeller just shakes but doesn't rotate.
@bluehallu So I have done some testing with the new version of the Tekko32 F3 and can confirm for me it behaves the same as the old version. Flies poorly on 96kHz with significant loss of authority at zero throttle and death rolls on punchouts. Flies better on 48kHz with some minor loss of authority after full throttle punch and chop, particularly with a full pack. I need to test with bidirectional dshot turned off.
@sskaug I hope this information helps with your investigation. Two different versions of the Tekko32 F3 board affected. Seems to be strongly related to PWM frequency and battery voltage with higher PWM and higher voltage being much more of a problem. I will test with BD DSHOT off and report back.
@bluehallu OK so I looked at your video and we are running almost IDENTICAL rigs. Same frame, Xing motors, stack, air unit. You seem to be having worse problems than me though so I want to help you get to where I am!
So, how are you mounting your capacitor? I have it mounted just behind the camera with two pieces of motor wire to connect to the battery pads, are you doing something similar?
I have 1700kV motors on 6S. Are you running similar kV? Are you using HV packs?
I'm running BF 4.2.0 filter sliders at 2.0, RPM filter on, dynamic notch set at 0 width percent, Q=250, Low 70Hz, High 350Hz. Everything else at defaults (incl. rates) do you run much higher rates?
@ChrisRosser I've tried default pids and filtering to no avail. Capacitor is mounted directly to the battery pads and held with TPU holder between standoffs. Motors are SmooX 2306/5 1800kv, packs aren't HV. If you're saying the new version has the same behaviour I'm bailing on Holybro. I've just bought a mamba F50 pro and won't ever be buying anything Holybro again, I guess I'll just sell the replacements as I presume they're good on 4S...
Does anyone else have the tekko32 f3 45amp newest revision with the extra + and - above the tekko32 logo. running tekko32_f3_C_32.7 firmware. I know that 32.7 is the latest stable release. If I go into flash, I see 32.7(sv) what is the (sv)? I know there has been issues with bidirectional dshot, which I intended to run, but am not sure its been addressed. I would like to run it, as I do on my 2 other Blheli32 quads, but not if I'm going to get desyncs. I will just keep bidirectional dshot off for now unfortunately.
@ChrisRosser Perhaps you can send your HolyBro ESC to @sskaug for investigation?
@Bwsbmw "32.7(sv)" simply means, that the hex file is not yet packed into the offline firmware resource, but will be downloaded while flashing.
Thank you, for that. So is the 32.72 hex have the corrections for the F3 and bidirectional dshot?
On Thu, Jul 23, 2020, 5:14 PM 4712 [email protected] wrote:
@Bwsbmw https://github.com/Bwsbmw "32.7(sv)" simply means, that the hex file is not yet packed into the offline firmware resource, but will be downloaded while flashing.
— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/bitdump/BLHeli/issues/464#issuecomment-663235657, or unsubscribe https://github.com/notifications/unsubscribe-auth/AIDVVI4TDB6GU5KWCYNB6BLR5CRZ5ANCNFSM4N7RXE6A .
@hydra Happy to arrange a tekko32 for @sskaug to look at. @sskaug how would it be best to get one to you?
I have the exact same issue @ChrisRosser describes with the same ESC. This behaviour of some motors not spinning at all after a rearm but fine after reboot is not something I've ever encountered or heard of before. Motor timing doesn't seem to affect it (Tried auto and 23, eventually happened on both) but 96khz definitely brings up this amongst other problems. On 96khz this is almost guaranteed to happen on the first punchout if not before, but aside from this the quad just flies terrible, lots of oscillations and loss of authority, even the motors make a strange noise.
I have contacted Holybro and received no reply. I find it very suspicious that this ESC has been pulled out of the market and a new version has been introduced with only one difference:
The PCB design uses a design in which the drive circuit and the control circuit are separated. This design broadens the overcurrent capability of the drive circuit, and at the same time reduces the electrical interference to the control circuit.
In my view, electrical interference doesn't manifest itself as a loss of performance but rather as a catastrophic failure like we're seeing. If Holybro is aware that the product had electrical interference problems they should recall it.
I have the brand new revision tekko32_f3_C with the upgraded blah blah blah. I have yet to do anything but hover test in the front yard since I just finished it. Running 32.7.2 bidirectional dshot is off for now. I totally agree, I didn't read about this till after I had ordered it from Holybro. I have 17 more days to contact them if I habe any issues. Timing auto(default), ive set it to 48khz. I dont dare turn bidirectional dshot on yet. I will be doing a full flight tomorrow, and see what it's flying like. I will try bidirectional dshot after I know it's flying ok with it off.
We have learned that there is a hardware issue with the B version of the Tekko F3. You can actually see this also from the second post here. There is a problem for 6S with some motors. So really there seems nothing we can do with FW or settings, and the proper way of handling it is to return the malfunctioning units to the vendor. Many units have been returned already.
@Bwsbmw If you're running 4S you are unlikely to have any problems. If you are running 6S I would suggest sticking to 48kHz PWM for daily driving. I found the RevC still had issues at 96kHz on 6S with Bidrectional DSHOT on. I haven't actually done any testing without bidirectional DSHOT on to see if that makes any difference. I would be interested to hear if you have weird flight behaviour on 96kHz with bidirectional dshot off?
@hydra. I do not know specifically in this case. But PCB design for ESCs is challenging - during acceleration situations like punchouts or roll stops, motor currents can reach hundreds of amps. Per ESC channel! Such huge current flows in the ground plane can cause disturbances to ESC signals - bemf sensing signals, MCU to driver signals, etc.